-LRB- CNN -RRB- -- Federal prosecutors are pushing to force the Arizona man accused of fatally gunning down six people and wounding 13 others , including U.S. Rep. Gabrielle Giffords , to submit a handwriting sample -- a request that he , thus far , has refused .

A motion was filed Monday , out of the office of U.S. Attorney Dennis Burke in Arizona , asking the court to compel Jared Lee Loughner to write out something so authorities can view his writing style .

The government wants the sample to compare with handwritten notes found in Loughner 's residence that include mentions of Giffords `` as well as references to guns and bullets , '' according to a court document . It says he has resisted such requests to date , `` arguing that the court lacks authority '' to force him to provide a sample .

`` There being no other avenue to obtain the defendant 's handwriting exemplar , the government now seeks an order to compel , '' prosecutors wrote in the motion .

Last Thursday , a federal grand jury returned a new indictment against Loughner in which he is charged on 49 counts -- including murder and attempted murder -- related to the shooting outside a Tucson supermarket in January .

The 22-year-old Tucson man was indicted on three counts of attempted murder , including one alleging that he tried to kill Giffords with a Glock semiautomatic handgun during the event she was hosting for constituents . After being shot through the head , the congresswoman is now undergoing rehabilitation at a medical facility in Houston , Texas .

The new indictment -- which supersedes an earlier one , which had fewer charges -- adds murder charges connected to the deaths of John M. Roll , a federal district judge , and Gabriel M. Zimmerman , a staff member for Giffords . Loughner also faces charges in the deaths of Dorothy J. Morris , Phyllis C. Schneck , Dorwan C. Stoddard , and a child , referred to in the indictment as C-T G. Nine-year-old Christina-Taylor Green was among those killed in the shooting .

Autopsy reports released Monday showed that Zimmerman , Schneck and Stoddard suffered fatal head wounds , while the three others were shot in the chest .

Loughner could face a death sentence if convicted , Burke said last week , although prosecutors have not said yet whether they will seek the death penalty .

Loughner , who is being held by authorities in Arizona , is expected to be arraigned on the new charges Wednesday in Tucson , the district attorney 's office said .

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Jared Loughner is refusing the government 's request for a writing sample

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Authorities want it to compare with notes found in his home after the shooting

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Loughner faces 49 charges related to a mass shooting outside a Tucson market